1. Field
Example embodiments generally relate to apparatuses and methods for controlling movement of components. The controlling may involve, for example, allowing, limiting, and/or preventing movement. The components may be integrated components. Example embodiments also relate to nuclear reactor plants and to apparatuses and methods for controlling movement of components in the nuclear power plants.
2. Description of Related Art
A reactor pressure vessel (“RPV”) of a boiling water reactor (“BWR”) may have a generally cylindrical shape and may be closed at both ends (e.g., by a bottom head and a removable top head). A top guide may be spaced above a core plate within the RPV. A core shroud, or shroud, may surround the core and may be supported by a shroud support structure. The shroud may have a generally cylindrical shape and may surround both the core plate and the top guide. There may be a space or annulus located between the cylindrical RPV and the cylindrically shaped shroud.
In a BWR, hollow tubular jet pumps positioned within the annulus provide the required reactor core water flow. The upper portion of a jet pump, known as the inlet mixer, may be laterally positioned and supported by related art jet pump restrainer brackets. The restrainer brackets may support the inlet mixer by attaching to the adjacent jet pump riser pipe. The lower portion of a jet pump, known as the diffuser, may be coupled to the inlet mixer by a slip joint. The slip joint between the inlet mixer and a collar of the diffuser may have an operating clearance that accommodates relative axial thermal-expansion movement between the upper and lower portions of the jet pump. The operating clearance also may permit leakage flow from the driving pressure inside the jet pump.
Excessive leakage flow may cause oscillating motion in the slip joint, known as flow induced vibration (“FIV”) or slip joint leakage flow induced vibration (“SJLFIV”), which may be a source of detrimental vibration excitation in the jet pump assembly. While related art jet pump restrainer brackets may provide system stiffness that mitigates vibration of system components, SJLFIV may still occur between the inlet mixer and diffuser. The slip joint leakage rate may increase due, for example, to single loop operation, increased core flow, and/or jet pump crud deposition.
Thermal and pressure displacements of the shroud and RPV may diminish alignment interaction loads in the jet pump assembly that are beneficial in restraining vibration, such as a lateral force in the slip joint. The resultant increased vibration levels and corresponding vibration loads on the piping and supports may cause jet pump component degradation from wear and fatigue.
High levels of FIV may be possible in certain jet pump designs at some abnormal operational conditions having increased leakage rates. Therefore, it may be desirable to provide a jet pump assembly that has a lateral load in the slip joint area to maintain the stiffness of the interface between the inlet mixer and diffuser to prevent oscillating motion and suppress FIV.
Related art apparatuses and methods are discussed, for example, in U.S. Pat. No. 4,285,770 to Chi et al. (“the '770 patent”); U.S. Pat. No. 6,394,765 B1 to Erbes et at (“the '765 patent”); U.S. Pat. No. 6,438,192 B1 to Erbes et at (“the '192 patent”); U.S. Pat. No. 6,450,774 B1 to Erbes et at (“the '774 patent”); and U.S. Pat. No. 6,587,535 B1 to Erbes et al. (“the '535 patent”). The disclosures of the '192 patent, the '535 patent, the '765 patent, the '770 patent, and the '774 patent are incorporated in this application by reference in their entirety.
Related art apparatuses and methods also are discussed, for example, in U.S. Patent Application Publication Nos. 2008/0031741 A1 to Torres (“the '741 publication”); 2010/0242279 A1 to Sprague et at (“the '279 publication”); 2010/0329412 A1 to Ellison et al. (“the '412 publication”); 2011/0052424 A1 to Bass et al. (“the '424 publication”); 2011/0135049 A1 to Wroblewski et at (“the '049 publication”); and 2011/0176938 A1 to DeFilippis et al. (“the '938 publication”). The disclosures of the '049 publication, the '279 publication, the '412 publication, the '424 publication, the '741 publication, and the '938 publication are also incorporated in this application by reference in their entirety.
Additionally, related art apparatuses and methods also are discussed, for example, in U.S. patent application Ser. No. 12/982,280 to Sprague et al. entitled “Method and Apparatus for a Jet Pump Three Point Slip Joint Clamp” (“the '280 application”). The disclosure of the '280 application is likewise incorporated in this application by reference in its entirety.
Moreover, related art apparatuses and methods are discussed, for example, in World Intellectual Property Organization (“WIPO”) International Publication No. WO 2011/035043 A1.